# Mechanisms of memory CD4 T cell-mediated immune protection against Chlamydia

> **NIH NIH R01** · UNIV OF ARKANSAS FOR MED SCIS · 2020 · $375,091

## Abstract

PROJECT SUMMARY/ABSTRACT
Chlamydia trachomatis genital infection is the most commonly reported infectious disease in the United States
with no vaccine available. The rational design of a chlamydia vaccine requires improved understanding of the
protective immune mechanisms within the female reproductive tract (FRT) mucosa. Although it is broadly
accepted that CD4 T cells play a predominant role in protective immunity against Chlamydia FRT infection, the
mechanisms underlying CD4 T cell-mediated immune protection remain to be poorly understood. This
application proposes to develop a thorough understanding of the differentiation, anatomical distribution and
maintenance of protective memory CD4 T cells and how they are stimulated to confer protective immunity
against Chlamydia. We recently generated several Chlamydia-specific MHC Class II tetramers, which allow for
the first time direct visualization of endogenous, antigen-specific CD4 T cells following Chlamydia FRT
infection. Using these unique tools, we specifically propose to (i) examine the protective antigen-specific
memory CD4 T cell responses that lead to fast Chlamydia clearance from the FRT, and (ii) identify the major
antigen-presenting cells that stimulate the rapid protective memory CD4 T cell response in the FRT. We
anticipate that identifying the protective aspects of memory CD4 T cell responses to Chlamydia reinfection and
elucidating how immunological memory is maintained and reactivated in the host will provide important insights
into the future design of an urgently needed chlamydia vaccine.

## Key facts

- **NIH application ID:** 9906841
- **Project number:** 5R01AI139124-03
- **Recipient organization:** UNIV OF ARKANSAS FOR MED SCIS
- **Principal Investigator:** Lin-Xi Li
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $375,091
- **Award type:** 5
- **Project period:** 2018-05-18 → 2023-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9906841

## Citation

> US National Institutes of Health, RePORTER application 9906841, Mechanisms of memory CD4 T cell-mediated immune protection against Chlamydia (5R01AI139124-03). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/9906841. Licensed CC0.

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